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Designing A Modern "campaign Concertina" For Travel And Tropic

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#19 alex_holden

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Posted 26 September 2015 - 01:05 PM

Bonded leather is finely ground particles of leather bonded together in a vinyl base. If you have ever wondered why a cheap leather belt stretches and deforms easily then it is not (just) because you are too fat, it is because it is made out of bonded leather. Whenever you see a label that says 'genuine leather' then that really means it is bonded leather.


Interesting, it's long been a mystery to me how they get away with labelling that stuff as 'genuine leather'! It's like labelling an MDF cupboard 'made from genuine wood'. ;)

#20 Lars Hansen

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Posted 26 September 2015 - 03:12 PM

An idea:

 

As for bellows, it might be worthwhile to look into accordion-style bellows, like Harrington did for his square concertinas. http://www.concertin...herrington.html

 

If you want durability, stability, and fairly straightforward construction, it might provide a good starting point. The folded cardboard could be substituted with a more durable material (or be coated prior to assembly), and the corner gussets be made from a flexible artificial (I said it!) leatherette material. Given the rather small pieces and having no structural purpose apart from being flexible and airtight, you could get away with most types of material. You might not be able to skive these materials as fine as real leather, but all corners would be covered by either the cloth cover, the bellow tape or the metal corners. The metal corners, the cloth (you could use a non-cotton one for durability and damp-resistance), and the bellow tape (the current types available are quite strong and plastic-based) would provide you with some additional strength, compared with traditionally made bellows incorporating various plastics and leatherettes.

 

Norwegian diatonic accordion maker Olav Bergflødt has a series of photos on his facebook profile https://www.facebook.../olav.bergflodt that shows the construction of bellows from scratch to finish.


Edited by Lars Hansen, 26 September 2015 - 03:25 PM.


#21 alex_holden

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Posted 27 September 2015 - 12:54 AM

Thanks for the suggestion Lars. I think with either construction style it is the gussets that are going to be the most likely point of failure due to the material needing to remain airtight while constantly stretching/bending in more than one direction. I'm interested to have a play with the artificial bellows tape - perhaps it could be used for the hinges and top run of a concertina-style bellows?

#22 Lars Hansen

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Posted 27 September 2015 - 05:38 AM

Not really, as it will only work in straight lines. Hinge function only, so it needs something to take over in the corners, i.e. the metal corners of a 90 degree accordion bellow.

#23 Little John

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Posted 27 September 2015 - 12:13 PM

Interesting discussion about possible materials, but what about the usefulness of the instrument? Twelve notes is quite limiting. A lot of traditional tunes seem to fall in the range D above middle C to B twelve notes higher*. That's thirteen notes, but to play in the usual keys of G and D you would need to add two F sharps and a C sharp. That gives sixteen notes for the right hand. Personally I wouldn't bother with the project if I couldn't have at least that. So that's something else you might want to consider in the design.

 

*It might be just coincidence, but this range is what you get on a violin if you stay in the basic position and ignore the bottom string. It's also the realistically usable range of a whistle in D. These factors may have influenced the tunes as they were written and developed.

 

John.



#24 Chris Ghent

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Posted 27 September 2015 - 09:13 PM

Big difference between twelve notes and twelve keys each end...

#25 Little John

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Posted 28 September 2015 - 04:24 AM

Big difference between twelve notes and twelve keys each end...

 

True. I was basing my comments on Matthew's original post which states "I'm inclined to use my 12 buttons per side for an octave and three notes,  plus one chromatic per side, something like that."



#26 MatthewVanitas

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Posted 28 September 2015 - 09:17 AM

So far as the key array, the original Duett had 12 buttons per side in a proto-Maccann arrangement, with each side having a full chromatic single octave. It'd be possible to do the same on this Campaign Hayden:

 

 

  D# F  G  A  B   

     C  D  E  F# G# A#

                      C#

 

 

That said, I value range more than chromaticity, so I was envisioning something like this for playing in they keys of C and G:

 

 

 C  D  E  F#

F  G  A  B

 C  D  E  F#

 

Also that's a little more symmetrical and might lay out better.

 

Since the left-hand of a Duet has larger reeds than the right, would that mean that in theory an end which holds 12 low reeds might hold more than 12 reeds an octave higher? Or is the difference in reed size not significant? I see that in the original Duett the chambers are all the same size, but if Alex is CNC-machining the reedblock of plexiglass, would having differing-size chambers be much harder? If doable, would that allow us to add more buttons to the right side (at a little added cost for more reeds and keywork)?

 

I've been playing around with the Duettina app, playing tunes I know, song accompaniment, etc and I can certainly make do with 12 a side, three rows of four, as shown. If I could add notes, my top choices would be to add a fourth row of "F G A" to the top of the right-hand side, but again in the simplest case I can work with 12. I've played *much* more limited instruments in my time, so I'm not unduly worried about the limitations of this one, particularly if it's mostly for playing alone, or even easier if I'm using it for chord/drone stuff to accompany my voice.

 

 

Speaking of drones, one idea I mentioned to Alex was that if he wanted to try messing with the pre-made McMaster-Carr synthetic 5" square machine bellows, without designing a whole big spiel around it, perhaps those bellows could be used to make a keyless small square concertina, with basic/inexpensive materials, with just four reeds in DAda to serve as a drone box for voice accompaniment? But even with the best of labor/material saving that's probably not the most cost-effective way to replicate an Indian shruti-box for a Anglo-Celtic environment, unless someone was really keen for such a thing. Alternately, one useful way to try out the McMaster might be just using it to build a tuning rig? That way you'd have a rig that didn't tie up any time in making, doesn't wear out over time, etc. Just tossing out some brainstorms (practical or no).

 

 

@JimMacArthur: Jim, do you have any photos of your MIDI prototype to share, or are those still close-hold at this stage? Very curious to hear how it's working out, if you feel like updating the MIDI concertina thread in General at some point. Neat stuff happening in the concertina world these days! Are we in perhaps the most innovative period of concertina history since the Interwar Years?


Edited by MatthewVanitas, 28 September 2015 - 09:17 AM.


#27 JimMacArthur

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Posted 28 September 2015 - 07:42 PM

https://wiki.harvard...501.jpeg?api=v2

 

That pic is missing the rubber trim around the faceplate, which is also finished in gloss black sign ink, like the corner pieces.  Because I was basically designing around the bellows, the design took on a sort of mid-20th-century industrial feel: bakelite, rubber, and tin.

 

I've been neglecting my concertina wiki page, but I'll start loading pics onto it, concentrating on the bellows assembly.  And everything else, too.  Schematics, mechanicals, code, whatever you want.  I'll re-post when I do.



#28 MatthewVanitas

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Posted 29 September 2015 - 04:42 AM

Wow, Jim, that's looking really cool! I'd seen your faceplate in the other thread, but not realized that it's actually a square instrument with tapered corners to get the hexagonal look. And really digging your overall industrial aesthetic!

Once you get done with your prototyping, it'd be interesting to do some poking at the specs and see if this could be a design you could license out to a tech to produce a run of bodies, and take orders for a few dozen complete or kit instrument. Depending how things have stabilized in my new career by then, I might be able to help out there. Not to put the cart before the horse or anything, for now I'm just excited that you have a cool prototype to show us, and looking forward to hearing about how it develops further.


I still definitely want a traditional-based Campaign Duet since I've wanted such a critter since Afghanistan. But I do have long term aspirations to own a good MIDI Hayden, and think that having a quality/affordable MIDI concertina on the market would be a valuable addition to concertina culture, and also lure in a chunk of non-concertina MIDI enthusiasts who would appreciate the concertina's dynamics control and portable package.

Edited by MatthewVanitas, 29 September 2015 - 06:35 AM.


#29 Jake Middleton-Metcalfe

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Posted 29 September 2015 - 05:12 AM

About carbon fibre for the soundboard:

 

I actually have no idea what effect this might have on the sound - the thing is with my build is it was a learning experience and a prototype on which to try lots of new ideas. The problem with this is that I changed so many variables at once that its hard to tell which variables are resulting in the soft sound. My feeling is that as my instrument is larger than a conventional concertina it is playing at a lower preassure which as chris Ghent notes means I have to press quite hard - not great. It must be a combination of that and the small holes making it quiet - so as for the carbon itself I am not sure to what degree it is deadening the sound - for a sound board I am not sure what effect that might have. It could be an interesting experiment.


Edited by Jake of Hertford, 29 September 2015 - 08:00 AM.


#30 MatthewVanitas

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Posted 01 October 2015 - 04:28 AM

Bouncing around some material ideas with Alex: maybe Perspex for all the "wood" components, aluminum ends, carbon fibre soundboard, and for the handrails linen micarta (fabric frozen in thermoplastic). Then the outside of the Perspex body could be veneered with a more attractive and scratch proof plastic, like a Bakelite or tortoiseshell pattern. That way we'd have an instrument with a nearly weather-impervious body, and the parts relatively easily made on a CNC mill.

CAD layout stage coming up later to check on reed geometry, but I keep messing with the 24b array on my Duettina app and it's limited but certainly usable, so I'm good with 24 at the minimum. That also gives enough buttons to be able to re-use most of the design again if someone were to want a small travel Anglo, whether a 20b array with the added chromatics for Irish, or the Edgley-Herrington 24b array if that would be kosher to replicate.


Re the fretwork: Alex wants to avoid anything too geometric and inorganic, so I've been googling "modern ironwork" and similarly for other schools of architecture, and found a cool few ideas:

jg4bv9.jpg

And here's some work from a house in Barcelona designed by Gaudi:

8wljsx.jpg

Edited by MatthewVanitas, 01 October 2015 - 05:30 AM.


#31 Jake Middleton-Metcalfe

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Posted 01 October 2015 - 07:41 AM

that ironwork is pretty funky - it could probably be easily milled also as there are no sharp points at the end of each hole, which makes milling traditional patterns inappropriate



#32 alex_holden

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Posted 01 October 2015 - 10:48 AM

Interesting. The second one looks like oil floating on water, or maybe cells under a microscope.

#33 rlgph

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Posted 02 October 2015 - 07:05 AM

There have been a couple of wonderings about a carbon fiber sound board. I have a carbon fiber travel guitar that may give some clues. Its sound is pretty loud, as loud as a comparable wooden top, with quite a bit of sustain. The tone is pretty close to that of wood, with a very slight metallic component. There are currently several makers of CF guitars, and i understand each has its own characteristic tone. The Composite Acoustic guitar i have was one of the first to sound very similar to a wooden guitar, apparently getting close tone-wise by molding in top braces (though not needed for strength).

#34 alex_holden

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Posted 02 October 2015 - 11:04 AM

From previous discussions on the forum, it seems the soundboard in a concertina has a different effect on the sound from that of a string instrument, acting more as a filter than a resonator, and a soundboard with a hard surface might produce a harsher tone. I've been wondering if I might need to add some sort of baffle to counter the effect if it ends up too harsh.

Of course we're going to have the same problem as Jake: this is such an unusual instrument that if it ends up sounding unlike a traditional concertina, we won't know which of its many non-traditional materials and design features are causing the difference(s).

#35 MatthewVanitas

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Posted 08 October 2015 - 10:13 AM

Puzzling out coatings for a plexiglass frame so it'll be more aesthetic on the outside. Alex suggested adhesive vinyl sheeting since itd be easy to apply, easy to replace if cosmetically damaged, and comes in a lot of patterns. He also considered "pick guard material" such as used in guitar faces, but apparently it's hard to nail down quite which kind of plastic each maker uses to figure out what's conducive. I'd also thought about hydrodip, which is a really popular costing these days for vehicle parts, etc and seems to hold up to even regular outdoor use, but hydrodip really shines for complicated surfaces, follows curves, etc so it's almost too versatile for just veneering a frame (or is it?). Hydrodip does come in some cool retro Bakelite-style patterns I like so that's what made me think of it.

So far as bellows, while I do think it'd be cool to find a good synthetic, and I agree that if concertinas had been invented in 1990 then leather wouldn't have become the go-to choice. That said if there just isn't a good alternative, properly treated leather might be viable, though with the acceptance that I might need to replace it every ten years vice every fifty. I've noticed that though my leather shoes and belts keep growing mold here in Liberia in monsoon season, the leather bag for my Swedish bagpipe (the only natural material on the instrument since all the rest is polymer) is mold-free; something about whatever treatment is applied to bagpipe leather? It's a slightly fuzzy external surface too, and even synthetic things with fuzzy surfaces (like headbands for LED lights) grow mold here, so there must be some treatment keeping it clean. I need to find out what that chemical is and apply it to my boots...

Edited by MatthewVanitas, 08 October 2015 - 10:55 AM.


#36 alex_holden

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Posted 08 October 2015 - 01:08 PM

Hydrodip does come in some cool retro Bakelite-style patterns I like so that's what made me think of it.


I'm wondering if I correctly understand what you mean by Bakelite - to me it's a smooth cast thermoplastic that usually comes in plain terracotta, black, white or ivory. Very occasionally I've seen antiques with a sort of mottled brown pattern:
https://en.wikipedia...elite_radio.jpg
 

So far as bellows, while I do think it'd be cool to find a good synthetic, and I agree that if concertinas had been invented in 1990 then leather wouldn't have become the go-to choice. That said if there just isn't a good alternative, properly treated leather might be viable, though with the acceptance that I might need to replace it every ten years vice every fifty.


I tend to agree; at least we know that a good quality goatskin will stand up to many years of playing if we can manage to stop it rotting. Do the locals have any advice to offer about preventing mildew on leather goods - presumably it's a common problem?





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